Hey everybody. I could use some help please in diagnosing a weird issue I am having .. when I go out to my car after it has been sitting awhile (usually notice this in the morning), the buttons on the handles to unlock the car do not work. I have tried driver and passenger door. Sometimes, if I press it a dozen times, it finally unlocks. No issues with the keyfob though, it works fine and right away. However, for the remainder of the day, the buttons on the handles will work. Any reason why the buttons wouldn't work when not used for awhile? Thanks for the help.

 

^^^
Have you tried replacing the battery in your key Fob?

Telcoman

 

I haven't. But it didnt make sense to me that it would be the battery because when I press the unlock button on the fob it unlocks the car without issue. And then all day it works fine.

 

The key fob in our Nissan/Infiniti has 2 separate wireless signals going on. The traditional keyless entry signal works exactly like any other Nissan 2004 and newer. The prox key system is an entirely separate subsystem in the car. I know in my coupe, there are 4 transponders I believe: one in each door handle, one in center console, and one in the trunk on the seat back. Door transponders are for the rubber button on the door handle, center console transponder is for push-to-start, and trunk transponder is for the trunk. Having a key near the trunk, for example, won't allow your door handle to open. These 4 transponders "talk" with the transceiver in your key fob. Yes, the key fob uses one battery for both functions, but the battery condition can affect keyless entry and prox key differently. Try this for troubleshooting:
-when prox door unlock is not working, go to the trunk and see if it'll open with prox key, and/or also try passenger door.
-replace battery

In my car, I had a low-batt warning on the DIC every time I started the car, but my keys worked fine.

 

Thank you for the detailed response. I did try the passenger door the other day when it wasnt working on the driver side and no luck. Haven't tried the trunk though. Theres only really 2 things in play right: the key fob and then the sensors in the doors/trunk. So either all sensors have failed at the same time or something with the fob. I guess the battery cant be that expensive so sounds like I should just replace it and see if that does the trick. Is there something that controls all 3 sensors in the doors/trunk that could be an issue? Thanks

 

@takemorepills What about the passive portion of the fob that's used to start the car when the fob battery is dead. There's a slot for it to the left and bottom of the steering wheel.

The fob takes a cr2032 battery. Same type as used by most computer motherboards. 3V, 20mm diameter, 3.2mm tall.

 

That passive portion is basically a NATS system that Nissan used prior to the transceiver setup that prox key needs. The passive system doesn't require power, it gets powered by being in close proximity (inserted into the port on the G37) to the antenna that's inside (the G37 port) or near the ignition cylinder on keyed vehicles.

 

Without checking the G37 FSM to be sure, I would guess that the prox key system also is tied in to the ECM, and the ECM makes the decisions.

As a betting person, I would bet your fob either has a low battery or would be defective long before the in-car devices would be suspected of being faulty. Think about the rough life the fob has, compared to the protected life of the devices inside the car (unless car was flooded)

 

Is there a sync procedure for the door buttons? All of mine work but the drivers door. The entire door was replaced after an accident, i just assumed it didn't work but wonder if i can sync it

 

If the door contains a transponder that is not the one your car was built with, then it will likely require the car to be connected to CONSULT-II (or newer) to be synched with the car.
should be the same as older Nissans I've worked on, the older NATS system would require CONSULT-II even for simply replacing the antenna around the ignition switch.

If you can get the old transponder from your wrecked door, that'd be an easier approach. CONSULT-II is only available from the dealer, unless there's bootleg versions available these days, but since it's a security module, good luck with the bootleg stuff